1. Field of the Invention
The present invention generally relates to plug assemblies and, more particularly, is concerned with an insulation displacement plug assembly and a method of making the assembly.
2. Description of the Prior Art
Dual blade plug assemblies have been used to make electrical connections for many years. These dual blade plug assemblies have either a polarized or non-polarized feature. The process of making a plug assembly can be a challenge. Several methods exist for manufacturing dual blade plug assemblies.
One method involves joining a pair of terminals and one plug housing in an assembly machine. Two wires, unstripped, are threaded through the plug housing prior to assembly. When the wires are located properly in the assembly nest with the plug housing, a machine inserts the two terminals into the plug housing. During the insertion process, the back sides of the terminals scrape the insulation from the two wires. The terminals rest against the exposed conductors of the wires and thereby create an electrical connection.
Another method involves inserting a pair of metal terminals into a plastic plug housing. The plug housing's top portion is hinged. Two wires, unstripped, are threaded into the open plug housing and placed across sharp portions formed on the metal terminals. The hinged portion of the plug housing is then closed. During this process, the hinged portion of the plug housing presses the unstripped wires onto the sharp portions of the terminals. These sharp portions pierce the insulation making contact with the conductors of the wires. The hinged portion of the terminal acts as a strain relief holding the insulated wire in place.
Still another method involves first stripping insulation away from the wires to expose their conductor portions. Terminal blades are then mechanically crimped onto the stripped conductor portions of the wires and may be soldered. The wires with the terminals attached are inserted into a molding machine. The machine closes the mold tool onto the wires and terminals, injects molten plastic to form the plug housing and keeps the wires, terminals and molten plastic enclosed in the mold tool until cool. The machine then opens, releasing the wires mechanically crimped onto the terminals and permanently encased in a solidified plastic plug housing.
Yet another method involves first stripping insulation away from the wires and then threading the stripped wires through the back of a plug assembly. The bare conductors of the wires are attached to the terminals by threaded fasteners. The terminals are pressed into a plastic or phenolic plate that is part of the plug assembly. The wires are pulled back through the plug assembly and a cover plate is attached to the face of the plug assembly, protecting the consumer from the bare electrical wires underneath.
While these and other prior art methods for making dual blade plug assemblies appear to be satisfactory, none of them alone combines efficiency and reliability without incurring substantial costs in both equipment and labor. Consequently, a need still remains for a plug assembly and method of making the assembly which provides an optimum solution to the aforementioned problem in the prior art without introducing any new problems in place thereof.